Dual FMC required for RNP APCH B737NG?

[unkki]

Hello,

Is a dual FMC required for RNP APCH on the B737NG? We have some airplanes with 1x FMC.

In the FCOM there is SP 4.6 about RNP APCH (AR), but not about RNP APCH. The SP requires 2x FMC but does a normal RNP APCH also require 2x FMC?

Practical example, if the Jeppesen approach chart says RNP APCH with a LNAV and a LNAV/VNAV minima. Does this approach require a dual FMC setup to be flown?

Thanks in advance!

[aterpster]

Originally Posted by unkki

Hello,

Is a dual FMC required for RNP APCH on the B737NG? We have some airplanes with 1x FMC.

In the FCOM there is SP 4.6 about RNP APCH (AR), but not about RNP APCH. The SP requires 2x FMC but does a normal RNP APCH also require 2x FMC?

Practical example, if the Jeppesen approach chart says RNP APCH with a LNAV and a LNAV/VNAV minima. Does this approach require a dual FMC setup to be flown?

Thanks in advance!

RNP AR requires dual FMC and a lot more. RNP APCH is basic RNAV, but a new FAA notation. RNP APCH basically replaces "DME/DME of less than RNAV 1.0 not authorized."

I can, for example, fly RNP APCH in my Cessna 182 with a Garmin 400. Don't even need WAAS for LNAV minimums.

[unkki]

RNP APCH requires an RNP of 0.3 during the final approach segment thus making it RNP and not RNAV, correct? Highest RNAV = RNAV1 (terminal area).

This stuff confuses me...

From our manual:
RNP Approach (RNP APCH)

The PBN navigation specification RNP APCH is the official term for instrument approach procedures including the final approach segment. These procedures are often (and incorrectly) referred to as RNAV approaches, due to the (old) naming convention on Instrument Approach Charts (IAC), i.e. RNAV (GNSS) or RNAV (GPS) approaches. These procedures are gradually replaced by the new procedure name RNP RWY XX.

[Smythe]

RNP APCH has far less capabilities, thus far less requirements than RNP APCH AR or RNP AR.
RNP APCH is synonymous with RNAV(GPS)/ RNAV (GNSS)/RNAV (RNP)

With RNP APCH:
Initial and Intermediate segments RNP 1.0
RNP level down to 0.3 for Final Approach segment only.
You can have 1 turn prior to the FAF.
Missed approach not less than RNP 1.0

REQUIRED RNP APCH EQUIPMENT
The minimum equipment required to perform RNP APCH operations is:
One FMS
One GPS
One MCDU
One FD
One ND on the PF side
Two FCU channels
One PFD

I have always been amused with the missed approach RNP 1.0 min, as when going missed, it all falls apart from 0.3 to 1.0 (from the MAP!) This requirement really restricts procedures, as commonly, the tower is the controlling obstacle.

https://www.icao.int/MID/Documents/2...erspective.pdf

[Capn Bloggs]

Originally Posted by Unkki

Is a dual FMC required for RNP APCH on the B737NG? We have some airplanes with 1x FMC.

Our national regs (not aircraft specific) require one of everything for an RNP APCH LNAV. They require two of everything for an RNP APCH AR.

Originally Posted by unkki

The PBN navigation specification RNP APCH is the official term for instrument approach procedures including the final approach segment. These procedures are often (and incorrectly) referred to as RNAV approaches, due to the (old) naming convention on Instrument Approach Charts (IAC), i.e. RNAV (GNSS) or RNAV (GPS) approaches. These procedures are gradually replaced by the new procedure name RNP RWY XX.

That is not correct here. The (new) RNP approaches are named on the AIP charts as follows: an RNP APCH AR is called an "RNAV-X (RNP) Rwy XX"; and an RNP APCH LNAV is named "RNAV-Z (GNSS) Rwy XX. The "X" and the "Z" varies, depending on how many RNAV (RNP) approaches are published to that runway.

You obviously cannot have a simple title "RNP RWY XX" because that would not designate what type of RNP approach it is, given there are LNAV, LNAV/VNAV, LP, LPV and AR types of RNP approaches.

[aterpster]

Originally Posted by Smythe

RNP APCH has far less capabilities, thus far less requirements than RNP APCH AR or RNP AR.
RNP APCH is synonymous with RNAV(GPS)/ RNAV (GNSS)/RNAV (RNP)

With RNP APCH:
Initial and Intermediate segments RNP 1.0
RNP level down to 0.3 for Final Approach segment only.
You can have 1 turn prior to the FAF.
Missed approach not less than RNP 1.0

REQUIRED RNP APCH EQUIPMENT
The minimum equipment required to perform RNP APCH operations is:
One FMS
One GPS
One MCDU
One FD
One ND on the PF side
Two FCU channels
One PFD

I have always been amused with the missed approach RNP 1.0 min, as when going missed, it all falls apart from 0.3 to 1.0 (from the MAP!) This requirement really restricts procedures, as commonly, the tower is the controlling obstacle.

https://www.icao.int/MID/Documents/2...erspective.pdf

In the U.S. I can fly either of these two approaches with the most basic of RNAV IFR approach-capable navigators, such as a Garmin 400. I don't need a FD, or auto-pilot, or FMS, or dual displays, etc. Just a basic IFR panel and a basic CDI that displays the RNAV course. To fly to LPV minimums the example basic navigator would have to be a Garmin 430W. The note "RNP Apch" replaced the other note I have highlighted at Reedley.

[Smythe]

HAF:
TCH 24' What was the VGSI set up for??
Fairly high DA for WAAS

[Banana Joe]

The sooner they sort the naming on all the approach charts the better.

[aterpster]

Originally Posted by Smythe

HAF:
TCH 24' What was the VGSI set up for??
Fairly high DA for WAAS

The airport is used primarily by light aircraft. Note the LPV TCH is higher.

The LPV DA was dictated by terrain in the level section of the missed approach. FAA TERPs map below:

[Smythe]

Thanks,

a great example of the missed going to RNP 1.0 at the DA....

Funny the chart shows CAT D...

[aterpster]

Originally Posted by Smythe

Thanks,

a great example of the missed going to RNP 1.0 at the DA....

Funny the chart shows CAT D...

The FAA is divided into three "service areas." The Western Service Area held the view that whatever minimum runway length FAA airports standards supported for CAT D, the IAPs would include CAT D. The Central Service Area was just the opposite. The Eastern Service Area between the two. I say "was" because a new FAA order just came out reinventing the way instrument approach procedures evolve from inception to publication.

[Smythe]

That should clear things right up!

[aterpster]

Originally Posted by Smythe

That should clear things right up!

Every time they reorganize (or reinvent themselves) clarity is just around the corner.

[Cough]

And when you get that clarity, it normally muddies the waters in another direction. Until of course clarity for that new issue is published which....